In concentrated photovoltaic (CPV) modules, the incident light, in particular, the solar radiation, is concentrated on a photovoltaic cell by an optical system comprising, e.g., a mirror or a lens, such as a Fresnel lens or a spherical lens. For this purpose, the cell must be positioned at the focus of the lens. Such CPV modules are used, alone or combined in arrays, e.g., for generating current in photovoltaic power plants and can be mounted on tracking units in order to be optimally orientated toward the incident light, in particular, following the brightest region in the sky. Commonly, a CPV module or a CPV array comprises a lens plate and a receiver plate that is holding the solar cells. As described in WO 2007/093422 A1 and WO 2007/014716 A1, both parts are packed together by a frame that stabilizes the module mechanically and provides a housing to protect the inner module parts toward the environment.
It has been observed that the energy conversion efficiency of such systems is not constant over time and under different environmental conditions. Thus, there is a need for solutions to improve the overall energy conversion efficiency of CPV modules.